Sure, tools like Facebook, Twitter and Google provide a wonderful sense of what's happening this instant, anywhere around the world. But they're also being used to unlock mysteries that have existed since the end of World War II.

Millions of children were displaced or separated from their families during the Second World War. Many would never be reunited, and many had no family left.

As the war wound down, relief agencies photographed some of the surviving children. The BBC made routine announcements over the airwaves, attempting to reunite families. A long list of names was followed by a request: "Will anybody who recognizes himself write to the British Red Cross?"

Now, some 66 years later, the U.S. Holocaust Memorial Museum in Washington, D.C. is counting on the Internet to help fill the holes of history. The museum is using social media to gather stories of children who survived the Holocaust, in an online photo project called, "Remember Me?"

Jean-Claude Goldbrenner is approaching 70, and just like any other Internet user, he occasionally Googles himself. That's how, a few years ago, he discovered a photograph of himself as a boy — at the time, it was housed at the American Jewish Archives in Cincinnati. It's a photo he had never seen before, and he has no recollection of it being taken. For Goldbrenner, it's one more piece in the puzzle that is his past.

Goldbrenner was only 3 or 4 when the war ended and has very little memory of that time. Sitting in his home in Potomac, Md., he clarified that he was never really displaced.

His mother was killed at Auschwitz; his father survived the concentration camps at Buchenwald, Auschwitz and Treblinka. In the absence of his parents, other family members cared for him, and for that he considers himself fortunate. Vague memories bring him back to a farm, where he went into hiding with other children. Perhaps that's where his photo was taken, though he is not sure.

A more recent Google search returned that same photo, but it had moved from an archival box in Cincinnati to a website. It joined more than 1,100 similar photos of children on the Holocaust Museum's website.

But the power of the Internet is a double-edged sword. On one hand, it's now easier than ever to find what you're looking for — like a person. On the other hand: What if that person doesn't really want to be found? Theo Meicler, for example, considers himself content if not happy, now living with his wife in Houston, Texas. He's on Facebook, yes, at the urging of his children and grandchildren. But it has taken him decades to get to this place, and he's not one for trips down memory lane. That is, of course, where his rediscovered photo took him.

Case in point for a 21st-century quandary: The more we engage online, the less we can control what information we find, and what finds us. In the online world, your life is everywhere, all the time, a totally open book.

Memory is tricky territory, but the Holocaust Museum is used to that: Its mission is to preserve stories and memories of war — even those that survivors are trying to forget. It's important so that future generations can remember, says Dr. Lisa Yavnai, a director at the museum.

Jean-Claude Goldbrenner was too young during the war to have many painful memories of that era; if anything, he wishes he had asked more questions. "Most of us either didn't think or didn't dare to ask questions," he says of his generation of survivors. "I think when you're young it's a question of didn't think, and when you're older didn't dare too much to stir these memories."

The U.S. Holocaust Memorial Museum wants to stir memories. It's using social media to gather stories before it's too late. "At this point we feel like it's really a race against time," says Yavnai, "because we want to help as many living survivors and their families as possible." If Facebook and Twitter are good for anything, it's racing against time.

"Remember Me" is one of a number of recent initiatives by the Holocaust Museum to employ the best available technology to document history. Last week, the museum also announced a project partnering with the genealogy website Ancestry.com. The World Memory Project, as it's called, relies on anyone with a PC to download software and join the effort to digitize, index and archive the museum's holdings.

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MELISSA BLOCK, Host:

From NPR News, this is ALL THINGS CONSIDERED. I'm Melissa Block.

ROBERT SIEGEL, Host:

Unidentified Man: This is the third broadcast made on behalf of 45 allied children who've been Nazi captives and have no homes.

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SIEGEL: Claire O'Neill has our story.

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BLOCK: Will anybody who recognizes himself write to the British Red Cross?

LISA YAVNAI: You can just imagine how long it would take someone to write a letter, for the letter to be opened and then for the child to be located back in Europe.

YAVNAI: The difference now is that with the social networking, with Facebook and Twitter, it's instant. We put this website up. And within 24 hours, we got our first identification.

NEILL: Yavnai's work is part of an online effort to find some 1,100 children now in their 60s, 70s and 80s whose photos the museum has to get their stories and to spread awareness about war from a child's perspective.

YAVNAI: These are some of these photos.

NEILL: She's looking through a box of carefully preserved prints. Faces of children from two months to 18 years old, mostly Jewish, a wide range of nationalities - French, Ukrainian, Polish - many of them smile at the camera.

YAVNAI: And this is all we know. The name is written on the back with a stamp with the date August 14, 1946. This is when the photo was taken. We don't know anything else about this child except that aide workers took the photo to help identify her family.

NEILL: You don't need to be in D.C. to see the pictures. All you need is a computer and maybe a Facebook account to respond.

THEODORE MEICLER: I've been on Facebook for several years through my kids and grandkids.

NEILL: Theo Meicler saw his photo for the first time in an email from the museum at his home in Houston, Texas.

MEICLER: We are sitting in my office here and I have some pictures from that era. But I'm used to seeing those pictures all the time, so it doesn't stop me anymore. That picture, when I saw it, got my attention.

NEILL: In the photo on the website, Meicler looks to be about seven or eight, a full head of neatly combed hair, a fresh face. And right by that image you can see him today, 65 years later. His Facebook profile picture IDs a comment that he left. This is me indeed with more hair and less wrinkles, he writes. Not happy.

MEICLER: It was a photo that brought me back to a time that was not a very happy time in my life. I remember living in a house behind a railroad station where my father had a cased good manufacturing. I remember when two Gestapo agents came and arrested him.

NEILL: Meicler never saw his father again. He was reunited with his mother and brother after the war. But the picture stirs emotions that have troubled him for much of his adult life.

MEICLER: My father went through several camps, Buchenwald, Auschwitz, I think Treblinka.

NEILL: Jean-Claude Goldbrenner was too young to remember his father's departure, but he recalls his return.

JEAN: I have a memory of my father coming back totally emaciated, walking with cane. And that's probably the first memory I have of my father.

NEILL: Today, Goldbrenner lives in Maryland and was about two or three when his photo was taken. He rediscovered it by Googling himself. He's kept in touch with some of his childhood friends, especially when artifacts like these photos emerge.

GOLDBRENNER: I mean, that's my picture. And these are the two friends that I found at the time.

NEILL: For Goldbrenner's generation, the past has been a bit of a puzzle, pieced together through the years with photos and conversations and letters, like the ones his aunt sent him later in life, written by his mother. Through that correspondence, he learned the details of her death. She was killed, six to seven months pregnant, at Auschwitz. She was 28 years old.

GOLDBRENNER: Most of us either didn't think or didn't dare to ask questions. I think when you're young it's probably a question of didn't think. And when you're older, didn't dare too much to stir these memories.